East Lothian man Ken Reid embarks on the first leg of a marathon 750-mile cycle journey today in a bid to raise funds for audio books for people who are blind or partially-sighted.

He will be accompanied part of the way by Paralympian cyclist Laura Cluxton, who has the same degenerative sight loss condition as Ken, retinitis pigmentosa. His trip by tandem, taking in all four UK capital cities and Dublin, will mark the 30th anniversary of his going blind as a young man.

"There was no history of this condition in my family," says Ken, "and we had no idea how to deal with it. The condition is untreatable, so the doctors then had little more to say to me than to say I was going blind, and there was no-one else for me to talk to!

"So began my journey into sight loss. The prognosis was correct, I have gone blind. The rest of the journey has been a real one of discovery, with many highs and lows along the way."

Since then, Ken has gone on to be one of Scotland's most persuasive ambassadors for the needs of blind and partially-sighted people.

He will be waved off this morning from outside the Scottish National Gallery in Edinburgh by the city's Lord Provost Donald Wilson and supporters. He will cycle to Cairnryan, then ferry to Belfast from where he will cycle down to Dublin. From there he will take another ferry to Holyhead for Cardiff, and on to London. The trip should take around two weeks in all.

"The sight loss journey isn't an easy one," Ken says, "and I don't intend that my cycle journey should be easy either. I will be riding a tandem, sitting on the back seat, and helped by a relay of pilots. They will navigate us through the parts of the country they will be familiar with.

"By making this journey, I want to increase awareness of the journey that more than 100 people across the UK start every day towards sight loss."

Ken is also doing the epic ride in aid of the Royal National Institute Of Blind People's "talking books" audio library, which he insists is an absolute lifeline for those who can't read print.

An avid reader himself, without talking books, he says, a whole world of literature would be denied to blind people without this vital service. "But it costs RNIB £2,500 to produce each 'talking book'," he points out. "If I can raise £10 for each mile of my journey that's three new books for adults or children."

John Lauder, national director of cycling charity Sustrans Scotland, said: "We would like to wish Ken the best of luck on his cycle journey to all four capital cities this summer and hope he has a fantastic experience."

You can support Ken through his Just Giving page or text to donate – CCLE75 £5 - to telephone number 70070. Ken's progress can be followed on his Facebook page.